Subsea production station

ABSTRACT

This specification discloses a method and apparatus for the production of subaqueous deposits of fluid minerals through a subsea satellite system. The wells are drilled in a circular pattern through a template on the marine bottom serving also as base upon which the satellite body is installed. The production and control passages of each of the wells are connected to production equipment within the satellite body by separate connector units, independently lowered into place from a surface vessel, to form portions of fluid paths between the passages within the subsea wellheads and the production equipment within the shell of the satellite. Such an installation permits production through the satellite, installed on the template base, after only one of the wells has been drilled and completed. The produced fluids are separated and/or metered within the satellite prior to being transported to storage. Flowline tools are programmed to enter the various subaqueous wells through the connector units. Hydraulic circuitry and controls are provided for pumping the tools and chemicals down through the various wells and for retrieving the tools. Also disclosed is a hot water well utilized in conjunction with the heat exchanger within the satellite for warming the separated-off gases to prevent the formation of hydrates.

Unlted States Patent 1151 3,643,736

Talley, Jr. Feb. 22, 1972 [54] SUBSEA PRODUCTION STATION 3,401,746 9/1968 Stevens et al. ..l66/.5

[72] inventor: William A. Talley, Jr., Dallas, Tex. Pfimmy Examiner Marvin A Champion [73] Assignee: Mobil Oil Corporation Assistant Examiner-Richard E. Favreau Attorney-William J. Scherback, Frederick E. Dumoulin, [22] filed: June 1968, Alan G. Paul, Donald L. Dickerson and Sidney A. Johnson [21] Appl. No.: 740,520

[57] ABSTRACT 52 u.s.c1. ..l66/.5, 166/245, 166/267 This Specification discloses a method 5 PP for the 51 1m. (:1 ..E21b 43/01 Productlon f Subaqueous dePoslts 0f 3 through a [58] Field at Search ..l66/.5, .6; Subs Satelllte symm- The Wells drllled a f P l75/5 |o tern through a template on the marme bottom servmg also as base upon which the satellite body is installed. The production [56] References Cited and control passages of each of the wells are connected to production equlpment w1th1n the satelhte body by separate UNITED STATES PATENTS connector units, independently lowered into place from a sur' face vessel, to form portions of fluid paths between' the 3,504,740 4/1970 Manmng ..l66/.5 passages within the subsea weuheads and the production 3247672 4/1966 Johnson 166/5 X equipment within the shell of the satellite. Such an installation 313661173 1/1968 McIntosh permits production through the satellite, installed on the tem- 3'448799 6/1969 "166/5 plate base, after only one of the wells has been drilled and 314711174 10/1969 Mannmg" completed. The produced fluids are separated and/0r metered 3'495658 2/1970 Johnson within the satellite prior to being transported to storage. 215031516 4/1950 shrewsbury" "175/8 X Flowline tools are programmed to enter the various subaque- 2,959,016 11/ 1960 Parks 166/ .5 X ous n through the connector units Hydraulic circuitry and 3,111,692 11/1963 Cox ..166/.5 X controls are provided for pumping the tools and chemicals 3,261,398 7/ 1966 1 down through the various wells and for retrieving the tools. 3,298,092 1/1967 Dome? et Also disclosed is a hot water well utilized in conjunction with 3353364 11/1967 Blandmg at the heat exchanger within the satellite for warming the 3,373,806 3/1968 Stone ..166/.5 Separated; gases to prevent the formation of hydram 3,380,520 4/1968 Pease ..166/.5 60 3,391,734 7/1968 Towsend 1 66/5 22 Claims, 8 Drawing Figures PATENIEUFEBZZ 1972 3.643 .736

saw 1 OF 6 INVE NTOR WILLIAM A. TALLEY,JR.

Maj/g4 ATTORNEY PATENTED FEB 2 2 I972 SHEET 2 [IF 6 INVENTOR WILLIAM A. TALLEY, JR.

ATTORN EY PAIENTEI] F EH 2 2 I972 sum 3 OF 6 INVENTOR WILLIAM A. TALLEY,JR.

am, away ATTORNEY PATENTEUFEBZZ m2 3, 643 736 sum 4 0F 6 WELL 8 WELLHEAD PRODUCTION EQUIPMENT I SYSTEM I l I I8 I TO STORAGE SUPPLY SYSTEM CLEAN,DEAD OILJ l I IN SEPARATORS 72l 4 I90" |NVE bTT5 I78 WILLIAM A. TALLEY JR. F IG. 5

QAJPW/ ATTORNEY PATENTEUFEB22 m2 3, 543 735 SHEET 5 [IF 6 T0 WELL 8. WELLHEAD 76 EQUIPMENT I56 I57 208 I20 V /2O4 r2O5 209 F F 'ms umo 238 206/. L 108 I 26 I30 I341 m '64. '02 I} TO FLARE 72' DEAD on. SUPPLY 7-$FOR TFL FLUID 3 234 d 174 .SUPPLY SYSTEM 21:16 236 I8 K 232 I 220 TO I66 33?;35 E 230 T0 STORAGE r2 2:

TO STORAGE 0R DISPOSAL MEANS CLEA DEAD on. SUPPLY FOR TLF FLUID SUPPLY SYSTEM TO STORAGE INVENTOR WILLIAM A. TALLEY JR.

ATTORNEY PAIENIEUFEB 22 I972 sum 8 OF 6 WILLIAM A. TALLEY, JR.

ATTORNEY SUBSEA PRODUCTION STATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a subsea satellite station in which the problems associated with laying underwater flowlines are alleviated by the drilling and completing of individual wells in groups closely encircling subsea satellite stations. More particularly, the invention relates to a subsea satellite station designed in such a manner that groups of wells are drilled and completed adjacent an installed satellite body.

2. Description of the Prior Art Since its inception, the offshore oil and gas industry has used bottom-supported above-surface platforms as the principal mechanism for the installation and support of the equipment and services necessary for the production of the subaqueous mineral deposits. As the industry has developed over the years, it has extended its search for offshore minerals from its birthplace, producing oil and gas in the shallow coastal waters off California, and the Gulf of Mexico, into areas where, because of excessive water depth and/or other local conditions, the bottom-supported platform is not as economically or technologically feasible.

While theoretically there is no limit to the depth for which a bottom-supported platform can be designed and installed, experience to date indicates that platform costs increase almost exponentially with the increase in water depth. Thus, the presently estimated costs of a platform to carry the production facilities for a field in 400 feet of water or more are so high as to indicate that such an installation cannot be justified economically for any but the most productive fields. Furthermore, the few bottom-supported above-surface platforms that have been designed and built for use in 300 feet or more of water depth have almost invariably suffered leg failures of one type or another.

A possible solution is to install the production facilities on a floating platform, as is described in the H. D. Cox U.S. Pat. No. 3,111,692, issued Nov. 26, 1963, which can be maintained in position in a field by either a fixed multipoint mooring system of anchors and anchor lines, or by a dynamic positioning system. The above solution involves the expense of continuous maintenance and surveillance of the locating system as well as the associated problems and expense of maintaining the multiple flexible lines connecting wellheads on the marine bottom with the continuously moving floating production platform, and the potential hazard, of this system, to the hoses, in the event of a failure of the fixed mooring or dynamic positioning systems.

Another consideration is that, in many areas of the world, local conditions other than water depth impose critical limitations on the use of bottom-supported production platforms. In arctic areas, a bottom-supported platform must be built to withstand the forces imposed by ice that forms on the water surface during the winter months of the year, and in many such areas all year long. Furthermore, any above-water production platform is subject to the mercy of the wind and waves, especially those occurring during hurricanes and other violent storms. In the arctic areas these storms can be exceeded by the forces exerted against the platform by movement of the thick ice layers that freeze on the surface of the water. For example, in Cook Inlet, Alaska, the local extremely high tidal movements on the order of 30 feet or more cause very fast tidal currents in the Inlet, with velocities of up to 8 to 10 miles an hour or more. These very rapid currents carry with them the heavy pack ice that forms on the surface of the Inlet, so that it bears with tremendous force against any fixed structure, such as a production platform, that should be installed in its path.

In still other areas it is not adverse natural, but manmade, conditions that restrict the use of bottom-supported abovesurface production platforms. Among such conditions could be listed official and/or public objection to oil production facilities near public recreational or residential areas, and the presence of heavy marine traffic as in harbors, channels, rivers, and other navigatable bodies of water which make it necessarily advantageous to install as much of the production equipment beneath the water surface as possible. For example, the first known use of subsea wellheads is in Lake Erie where gas is produced from subaqueous formations beneath the heavily traveled lake.

Therefore, it would appear that where there is extremely deep water and/or adverse surface conditions, a fully subsea installation would be the most advisable solution. One method, as is shown by the J. A. Haeber U.S. Pat. No. 3,261,398, issued July 19, 1966, is to locate the individual pieces of production equipment on the marine bottom. Such an installation almost necessitates the use of robots such as shown in the G. D. Johnson U.S. Pat. No. 3,099,316, issued July 30, 1963. However, such instrumentalities are expensive and not without their own limitations and maintenance problems. Another solution is suggested by the H. L. Shatto, Jr. et al. U.S. Pat. No. 3,221,816, issued Dec. 7, 1965, wherein the production equipment for a plurality of wells is grouped within a satellite chamber adapted to be raised to the surface for repair and/or maintenance.

To utilize a subsea system, such as shown in the H. L. Shatto, Jr. et al. U.S. Pat. No. 3,221,816, discussed above, or the subsea system shown in the application of Warren B. Brooks et al., Ser. No. 649,959, filed June-29, 1967, where the individual wells are spaced out from the satellite station, requires long flowlines between each of the subsea wellheads and the satellite station. All of the problems associated with laying flowlines in deep water have not been solved yet, and furthermore, such operations even when technologically feasible are very expensive, prohibitively so for all but the most prolific of fields. Another problem is that of locating a particular subsea wellhead for repair or workover operations. Locating an object, such as a wellhead, in deep water requires sophisticated equipment and a great deal of time. By spacing a number of subsea wellheads across the marine bottom, the difficulties involved are compounded. One solution to the problem is shown in the Townsend application, Ser. No. 521,745, filed Jan. 19, 1966, now U.S. Pat. No. 3,391,734 wherein the wellheads are fabricated integrally with the shell of the satellite body. Wells are directionally drilled through the satellite body and are completed inside of the shell. Although such a configuration does away with the exterior flowlines, there is one very important defect in this type of system-the satellite body cannot be raised back to the surface for maintenance or repair operations without cutting all of the well casings hung therein.

SUMMARY OF THE INVENTION In accordance with the instant invention, a subsea satellite station, to exploit subaqueous deposits of fluid minerals, comprises a base template having a circular pattern of upstanding well conductor pipes affixed thereto through which wells are directionally drilled and are completed. The satellite body is releasably installed in a central position on the base template, encircled by the adjacent subsea wellheads of the wells drilled and completed through the base template. With the subsea wellheads close around the satellite body, each of the subsea wellheads can be fluidly connected to the satellite body with short, rigid connector units. This arrangement obviates the need for all individual flowlines except those connecting the satellite station with a production and/or storage facility. The large satellite stations, more widely spaced apart than would be individual subsea wellheads, are also easier to locate for workover and/or repair operations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial view of a subsea production system in accordance with the present invention;

FIG. 2 is a partially broken away enlarged view of one of the satellite stations shown in FIG. 1, illustrating the arrangement of the equipment therewithin;

101024 (HUI FIG. 3 is a schematic representation of a heat exchange system to be utilized within the satellite station also, but shown in less detail in FIG. 2;

FIG. 4 is a schematic diagram of the basic circuitry required to produce a plurality of oil and gas wells within a satellite statron;

FIG. 5 is a schematic diagram of a modified TFL FLUID SUPPLY SYSTEM;

FIG. 6 is a schematic diagram ofa modified PRODUCTION SYSTEM for producing a field having a high gas-oil ratio;

FIG. 7 is a schematic diagram ofa modified PRODUCTION SYSTEM for producing a field having a medium gas-oil ratio; and

FIG. 8 is a schematic diagram of a modified satellite station configuration for allowing the satellite body to be installed on a base template ofa satellite station prior to the completion of any of the wells through the base template.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Now looking to FIG. 1, a subsea system for producing fluid minerals, in particular gas and oil, from a subaqueous field by a plurality of subsea wellheads is illustrated. A plurality ofsubsea production satellite stations, generally designated 10, are spaced across a marine bottom 12, each satellite station 10 comprising a satellite body centrally positioned within a circular group of closely spaced subsea wellheads 14. The produced fluids from the subaqueous wells are directed through encircling subsea wellheads 14 into the satellite body 15 of the respective satellite station 10. The fluids being produced from the subsea wellheads 14 of each circular group are combined within the respective enclosed satellite body 15 and a first stage of separation (gravity) takes place. At least the liquid portion is then directed to a circular manifold 16 atop a central bottom-mounted storage tank 17 through a Shipping line 18, one shipping line 18 extending from each satellite station 10.

A floating master station 20, having power-generating and final stage separation equipment thereon, as well as being fitted out with offloading apparatus, is in fluid and electrical communication with the bottom-supported storage tank 17 through a tensioned tether pipe 22 extending from the storage tank 17 to a point just beneath the turbulent surface zone of the body of water and fixed at this point to a large subsurface buoy 24, A flexible conduit 26, containing a plurality of electrical and fluid flow paths, extends from the upper end of the tensioned tether pipe 22 to the floating master station 20. The produced liquid, collected in the circular manifold 16, is directed to the master station through a main shipping line 27 supported along the length of the tether pipe 22, and a fluid line forming a portion of the flexible conduit 26. The produced liquid passes through the final stage separation equipment on the master station where the pressure is normalized and dissolved gases are removed. The dead liquid is then transported to storage within the storage tank 17 through a line of the flexible conduit 26 connected to an axial passage in the interior of the tether pipe 22.

In the upper left-hand corner of FIG. 1 is illustrated the drilling of a well through a satellite base template, generally designated 28, which has been previously installed on a marine bottom along with a shipping line 18 for connecting a satellite station, when completed in conjunction with the template 28, with the storage tank 17. A drill string 30 is suspended from above the surface from a semisubmersible drilling vessel 32 and extends through a blowout preventer stack 33 mounted on one ofa plurality of upstanding well conductor pipes 34 forming a portion of the template 28. Illustrated in the lower portion of FIG. 1 is a manned submersible work vehicle, generally designated 36, of a type to be employed to assist in the subsea operations and for the dry transfer of personnel to the satellite station 10. The submersible work vehicle 36 has a pair of articulated arms 38 and 40 carrying a socket wrench 42 and a vise grip tool 44, respectively. The submersible work vehicle 36 is further equipped with a pivotable positioning motor 46 on each side (one shown) to assist in locating the submersible work vehicle 36 adjacent a satellite station 10 firstly when subsea operations are to be performed during the drilling operations and the installation of the satellite body 15 therewithin, and at later times during maintenance and workover operations. A lower port 48 of the submersible work vehicle 36 is connected with a rear compartment (not shown) within the shell thereof to permit a diver to be released at an installation site if one should be needed. The rear compartment is isolated from the pilots compartment, seen through the front view plate 50, so that a diver after exposure to deep water can be kept in compression in the rear compartment while the front compartment is maintained at atmospheric conditions. This general type of submersible work vehicle is 'well known in the art and specific vehicles of this type are more fully described in the application Ser. No. 649,959, filed June 29, 1967, of Warren B. Brooks, Charles Ovid Baker, and Eugene L. Jones, and the references cited therein.

Now looking at FIG. 2, the interior of the satellite body 15, as well as the satellite base template 28, are illustrated in more detail. The internal equipment comprises that necessary for a high gas-oil ratio, high-pressure field. The base template 28 comprises an outer ring 51 to which are rigidly connected the plurality of upstanding vertical well conductor pipes 34 through which subaqueous wells have been drilled. As shown, a dual completion wellhead 14 is mounted on the upper end of each of the well conductor pipes 34 in completing each of the respective subaqueous wells. The satellite body 15 is installed after the completion of all of the wells drilled through the respective base template 28. The satellite body 15 is shown to be cradled in a plurality of radially extending spaced arms 41 fixed to the base template 28. Threaded detent rods 43 extend through each of the arms 41 and through the shell of the satellite body 15 into receivers 45 fixed to the inner wall of the shell. The detent rods can be screwed into and out of engagement with the receivers by means of the socket wrench 42 of the submersible work vehicle 36. A hex nut 53, terminating in a conical guide, is affixed to the outer end of each detent rod 43. Support frames 47, having pillow boxes 49 in which the detent rods 43 are journaled, allow the use of long detent rods 43 extending radially out beyond the well conductor pipes 34.

A water well 52 is shown as having been drilled through the center of the base template 28 and is necessarily completed prior to the installation of the satellite body 15. After all of the wells, including the water well 52, have been completed, the satellite body 15 is lowered into place and is leveled and locked into the base template 28 in any suitable manner. There would be no reason why one water well could not be drilled through one of the well conductor pipes 34 on the ring 51 of the base template 28, if this should prove more convenient. The only disadvantage would be the elimination of one possible producing well. The W. F. Manning, U.S. Pat. applications Ser. Nos. 663,799, now U.S. Pat. No. 3,504,740 and 663,798 entitled SUBSEA SATELLITE FOUNDATION UNIT AND METHOD FOR INSTALLING A SATELLITE BODY WITHIN SAID FOUNDATION UNIT, and SUBSEA SATEL- LITE FOUNDATION UNIT AND METHOD FOR IN- STALLING A SATELLITE BODY THEREWITHIN, respectively. disclose alternate leveling and locking means as well as means for registering the installed satellite with respect to encircling wellheads.

The water well 52 is designed to provide a heat source for a heat exchanger unit (to be discussed below) to warm the produced fluids after a pressure out has been taken. The well water may also be directed through radiators in the portions of the satellite body 15 in which personnel are present to raise the interior temperature of that portion of the satellite body 15 above the ambient temperature at the marine bottom. In deep water the temperature at the marine bottom is in the range of 35 to 45 F., too cold for a man to work for long periods unless he is heavily clothed.

Each of the submerged dual completion wellheads 14 has a pair of upstanding tubing nipples (not shown), each being in fluid communication with a producing zone. Each of the pairs of tubing nipples is adapted to telescope into complementary passages of a stab-over connector unit, generally designated 54, comprising a pair of downwardly curving tubing sections 56 extending radially outward from within the shell of satellite body 15 and terminating in vertical lubricator sections 58. By means of the stab-over connector units 54, the production and control passages extending through the subaqueous wells are connected to manifolds within the satellite body 15 for the combining ofthe produced fluids through the satellite body 15 and/or for the injection of lift gas, or other fluids utilized in secondary recovery procedures, from the satellite body 15, to all or selected ones of the subaqueous wells. As shown in the embodiment of FIG. 2, the stab-over connector units 54 are permanently fixed with respect to the satellite body 15. Therefore, the satellite body 15 must be radially positioned quite precisely so that the stab-over connector units 54 can register with and telescope over the upstanding tubing nipples of the respective wellheads 14.

An escape hatch 60 is formed within the upper end of the satellite body 15 to permit the entry of an operator 62 from a diving bell or travel chamber, as shown in the Townsend application Ser. No. 521,745, filed Jan. 19, 1966, now U.S. Pat. No. 3,391,734, or a submersible work vehicle 38. The upper portion ofthe interior of the satellite body 15, within which the operator 62 is shown sitting at a panel 64, comprises a control section, generally designated 66, from which various operations, not normally programmed, may be controlled and from which stored information can be retrieved. Below the control section 66 is a production section, generally designated 68, containing the various equipment necessary to separate and meter the produced fluids as well as to pump treating fluids and tools through the various wells.

Beneath the floor of the production section 68 is a treating fluid storage section, generally designated 70. The treating fluid storage section 70 generally comprises an open-bottomed tank defined by the floor 71 of the production section 68 and the outer, generally cylindrical shell of the satellite body 15. The storage section 70 can be partitioned to permit the storage of two or more discrete well treating fluids needed in one or more operations. Although some plumbing extends through the storage section 70, it is substantially uncluttered to permit the storage ofa large quantity of well treating fluid.

Centrally located, within the production section 68, is a cylindrical heat exchanger unit 74. Equiangularly spaced around the heat exchanger unit 74 are a plurality of spherical separators 72. The produced fluids normally flow through the shell ofthe satellite body 15 by way of the tubing section 56 of the connector units 54. From a tubing section 56 the fluid is directed by a branch conduit 76 through an expansion valve (shown in FIG. 3 and to be discussed with respect thereto) into an upper heat exchanger manifold 78 located within the upper end of an insulated jacket 79 of the heat exchanger unit 74. Fluids, exiting from the manifold 78, flow down through a central pipe 80, leaving the heat exchanger unit 74 near the lower end thereof by means of conduits 82 (one shown) which lead the produced fluids into the individual separators 72.

The separators 72 in the satellite station 10 are of the gravity type to permit the separation of the gas from the oil without a substantial temperature drop in the separators, avoiding hydrate and paraffin deposition problems therewithin. A loss of 7 to 8 F. would be normal with such equipment. With a 1- minute retention time within the separator, all of the free gas will be removed, only the gas, dissolved in the liquid at the separator pressure, remaining for the secondary, or final, separation stage. While the separators planned for this installation have no water knockout feature, provision for removal of water from the oil could be provided if it was desirable at this stage of production. The pressure at which the separators 72 are designed to function may be governed by the depth at which the satellite station 10 is located since it is desirable to have sufficient pressure to lift the oil from the marine bottom to the master station 20 on the surface. In very deep water the produced oil may have to be lifted, at least in part, by powerdriven pumps. Where the satellite is connecting into a truck pipeline, rather than being transported away by tanker, the output pressure of the separators would be governed by the line pressure in the pipeline. Where the wells are producing with a wellhead pressure of, for example, 1,500 p.s.i. and the satellite station 10 is located in 2,000 feet of water, a 900- pound pressure drop will be taken, prior to introducing the produced fluid into the separators 72, to obtain a pressure of approximately 600 p.s.i., which would be that necessary to drive the oil from the marine bottom to the surface. Taking a pressure drop of 900 p.s.i. lowers the temperature of the produced fluids by more than 50 F. When considering a 10,000-foot well in which the produced fluids at the wellhead would be at from 150 to 170 F.,.at 50 F. the resultant temperature would be well within the formation temperature of hydrates and paraffins.

The heat exchanger unit 74, as shown more fully in FIG. 3, is located in the process fluid circuitry between expansion chokes 84, one located in each of the branch conduits 76, and the separators 72, providing a regulated flow of warm water as a heat source to increase the temperature of the mixed oil and gas on the downstream side of the choke 84 where a pressure cut has been taken, to prevent hydrate formation, minimize excessive paraffin deposition in the equipment, and restrict emulsion formation. The heat exchanger unit 74 depends upon well water obtained from the previously mentioned water well 52 (shown only in FIG. 2). The water is produced through a normal type of oil well completion and then flows through a variable choke 86 that regulates the flow and downstream pressure. In an example, using a 10,000-foot water well, the water at the upper end of the heat exchanger will also be in the range of 150 to 170 F. The water from the well 52 is directed upward through a conduit 88, entering the insulated cylindrical jacket at 79 of the heat exchanger unit 74, through the upper end thereof. The water travels down through the interior of the heat exchanger jacket 79, emerging from the lower end thereof in outlet line 90 from which the water is dumped into the sea. As the cold produced fluid passes into the manifold 78 within the upper end of the heat exchanger unit 74, after passing through the expansion choke 84 and a one-way valve 92, the fluid comes into indirect contact with the warmer water flowing around the manifold .78. From the manifold 78, the produced fluid flows through a hellcal coil 94 extending axially through the heat exchanger unit 74 and into a heat exchanger manifold (not shown) in the lower end thereof, and then out of the jacket 79 through conduits 82, each connected between one of the separators 72 and the lower heat exchanger manifold. A temperature sensor 96 is installed in at least one of the outlet lines 82 to act as a flow indicator and monitor mechanism to control the increase or decrease of the water flowing into the heat exchanger unit 74. By increasing or decreasing the size of the choke 80, the water flow is regulated to maintain the required temperature of the produced fluids entering the separators 72 (FIG. 2). Such a system also acts as a resource conservation in that large use of produced oil and/or gas to tire such heater equipment as would be otherwise needed is not required.

Looking back to FIG. 2, the liquids leave the separators 72 through respective liquid outlet lines 98, connecting the separators 72 with liquid output manifold 100 centrally positioned around the lower end of the heat exchanger unit 74. The combined produced liquid from the plurality of separators 72 is directed from the manifold 100 through a main oil outlet line 102 which is connected to the input end of a respective shipping line 18.

The liquid is removed, at the lower end of each of the separators 72, by the respective line 98 so as to also drain off all the water, entrained sand, and other impurities with the oil These impurities might otherwise impede the action of the separator 72 and cause a premature malfunction thereof. A

101074 nwsn shutoff valve 104 in each of the liquid outlet lines 98 is controlled in conjunction with a float (not shown) within each of the separators 72, to regulate the levels of the liquid within the separators 72. As shown, a mechanical linkage is utilized between the float and the valve 104. One of the electromechanical systems, well known in the art, could be substituted for the mechanical linkage. A clean oil line 108 is connected at a first end thereof into at least one of the separators 72, above the lower end thereof, to pick up oil from above the sediment level and below the low level of the liquid to provide substantially clean oil (with dissolved gas) for pumping a tool into and down through a selected well. Line 108, at the other end thereof, is connected to a first inlet of three-way two-position valve 110, the outlet of which is connected to the inlet of a gas-driven turbine-pump 112 to provide the clean oil under pressure to the TFL system. A second inlet of the three-way two-position valve 110 is also connected to a line 114 having a pickup head 116 in the fluid storage section 70 of the satellite body to provide a source of treating fluid for the turbinepump 112. Gas under pressure, for driving the turbine portion of the turbine-pump 112, is provided through a turbine gas supply line 118 extending from an auxiliary turbine (not shown in this view) which is supplied with produced fluid tapped off, through lines 119, upstream of the chokes 84. The clean oil under pressure from the pump portion ofthe turbinepump 112 is fed into a manifold (not shown in this view). From this last-mentioned manifold, the oil is pumped out, being selectively directed into one or more pressure lines 122, each pressure line 122 being connected into a bypass conduit section 124 just behind a TFL tool 126 stored therein. Each bypass conduit 124 is directly connected to a curved tubing portion 56 of a connector unit 54 for pumping the TFL tool 126 therein into the connected wellhead 14 and down a passage of the respective well. The separated-out gas, leaving a separator 72 through an upper pipe or gas outlet line 120, is combined with the separated-out gas from the other separators 72 in a ring manifold unit 128 encircling the insulated jacket 79 of the heat exchanger unit 74.

The separated-out gas can be, in various instances, utilized in production procedures, stored for eventual transportation to shore, or disposed of at the site of the offshore production field. A main outlet line 130, from the ring manifold 128, is shown directing the gas out of the satellite station 10 for disposal through one or more distant gas disposal wells (not shown) where the gas will be injected into shallow sands underlying the marine bottom. A safety regulator valve 132 is connected in the main outlet line 130 to allow gas to be bled off through a flare line 134 to the master floating station 20, if the pressure in the main outlet line 130 should rise above a predetermined value. If the gas obtained in the primary stage of separation is to be either disposed of by flaring or is to be stored for future transportation-to-shore facilities, it is conducted to the master station by shipping line (not shown), as described with respect to the produced oil. At the master station 20, the gas obtained from the primary stage of separation is combined with the gas obtained from the secondary or final stage of separation on the master station 20. If the gas is to be flared, a flare stack is erected above the master station 20. If the gas is to be stored, it is first compressed at the master station 20 and then is pumped down to a portion of the storage tank 17 or to a separate storage tank (not shown) nearby. As noted above, the gas from the primary separation stage may also be utilized in production procedures, the most common of these procedures being the utilization of the gas under pressure to provide lift pressure in the producing formations. A gas injection well for this purpose may be one of the wells drilled through the ring 51 of the template 28, in which case a separated-out gas is fed into the wellhead 14 through a respective one of the curved tubing sections 56 of a stab-over connector unit 54, or the injection well may be located at a distance from the satellite station 10, in which case an interconnecting flowline having a pressure regulator valve and a flare line, as described above with respect to injecting the gas into shallow sand formations, will be utilized.

FIG. 4 illustrates, in schematic form, a complete system, with the exception of a storage means, for the production of a low gas-oil ratio low pressure field. The fluid is produced in the portion of the system designated as WELL AND WELL- HEAD EQUIPMENT at the TD (total depth) 136 of a representative well, generally designated 138. In the well 138 is a storm choke 140 placed at approximately a 3,000-foot depth, below the normal lower limit of paraffin deposition, for safety purposes. Quarter-turned manually operated valves 142 are mounted on the wellhead 14 outside the satellite body 15 where they are easily accessible for operation by a man, robot, or a manned craft such as the underwater submersible work vehicle 36 illustrated in FIG. 1. In some instances, it may be desirable to utilize remotely actuatable valves in place of the manually operated valves 142. A high-low safety valve 144, also mounted on the wellhead 14 outside the satellite body 15, will automatically close shouldthe pressure in the well 138 exceed a specified high pressure or drop below a specified low pressure.

From the upper end of the wellhead 14, the fluid is directed through connector unit 54 to the portion of the wellhead equipment within the satellite body 15 where one or more TFL tools are stored in a storage chamber, designated by block 146. (A TFL storage device and a paraffin cutting tool, designed to be stored therewithin, are fully described in the patent application Ser. No. 579,571, of James T. Dean, entitled STORAGE SYSTEM FOR TFL TOOLS, filed Sept. 15, 1966, now U.S. Pat. No. 3,396,789. In FIG. 3 of the Dean patent, the incorporation of the described storage device in a fluid circuit for automatically maintaining a subsea well is shown.) The TFL storage chamber 146 is located in the previously described bypass conduit section 124, as is a TFL tool control valve 148, which remains closed except during TFL maintenance and/or testing. The branch conduit 76 contains a pressure indicator 150, an orifice meter 152, and a production wing valve 154. The production wing valve 154 is normally open while the well 138 is producing and closed during TFL operations. The branch conduit 76, through which the produced fluid generally flows, provides a path around the TFL storage chamber 146 and the closed control valve 148. When the well 138 is producing, the fluids flow from TD point 136, up through the storm choke 140, and the series of valves 142 and 144, of the wellhead 14, into the branch conduit 76. The pressure and flow rate of the fluid at the wellhead 14 are monitored at all times by the pressure indicator and the orifice meter 152, respectively, and representative signals are transmitted to, and recorded within, the control section 66 of the satellite station 10.

The produced fluid flowing through the branch conduit 76, past the interconnection with the bypass conduit section 124, leaves the portion of the system designated in the schematic diagram as WELLHEAD AND WELLHEAD EQUIPMENT and enters the portion designated PRODUCTION SYSTEM through a rotary variable choke 156. As the fluid passes through the variable choke 156, the pressure is lowered from that at the wellhead 14 to a pressure just above that necessary to drive the fluid from the marine bottom to the surface. From the rotary choke 156, the produced fluid is directed through a check valve 157 into a collector manifold 158. Branch conduits 76', each having a check valve 157', also shown as leading into the collector manifold 158, are connected to the wellhead equipment of the various wells encircling the satellite station 10. A pressure sensor 160 is mounted in the collector manifold 158 to monitor the pressure therewithin, a signal representative of which is transmitted to and recorded within the control portion of the satellite station 10. The rotary variable choke 156 is controlled in response to the pressures indicated by the pressure sensors 150 and 160. Three gravity separators 72 are connected, in parallel, to the collector manifold 158 through inlet lines 162, each having a shutoff valve 163 therewithin. The liquids, including oil and water, exit for the most part through lines 98 which empty into liquid collector manifold 164. This manifold corresponds to the circular manifold 100 shown in FIG. 3. From the liquid collector 101074 nah i manifold 164, the oil exits through the outlet line 102 and is transferred to storage through shipping line 18 after passing through a flowmeter 166. A clean oil outlet line 108, as previously discussed, extends from a point within each of the separators 72, from where substantially clean pure oil can be obtained, to a manifold 175, which empties in turn into the upstream end of a line 174 connected at its downstream end to an inlet port of a three-way two-position valve 180 in the TFL Fluid Supply System. The gas accumulating in the separators 72 passes out through a high liquid shutoff valve 168 located in the upper end of each of the separators 72, into a gas outlet line 120, which empties into a gas collector manifold 170. The major portion of the gas leaves the manifold 170 through the main gas outlet line 130, passing through an orifice meter 172, and is transferred to storage or disposal means. By disposal means is meant flaring" or shallow sand injecting" as previously discussed. The fluid pressure supply line 119 is connected between the bypass conduit 124, at one end thereof, and a manifold 159 at the other end. Lines 119' connect the bypass conduits of the other wells, which flow through the satellite station 10, with the manifold 159. The inlet of an auxiliary separator 161, where only a small pressure cut is taken, is in fluid connection with the manifold 159 through a highpressure line 165. The turbine gas supply line 118 is connected between the gas outlet of the auxiliary separator 161 and the inlet of the turbine of the turbine-pump 112 of the TFL FLUID SUPPLY SYSTEM to supply high pressure gas to the pump portion of the turbine-pump 112. The pressurereduced gas, from the gas discharge, or outlet, of the pump portion of the turbine-pump 112, is directed through a line 167 into the gas collector manifold 170. The liquids separated out in the auxiliary separator 161 are directed through line 169 into the liquid collector manifold 164. The purpose of the turbine-pump 112 is discussed below. If one of the separators 72 becomes plugged, the liquid will fill that separator and force the respective valve 168 to close. With this possibility in mind, the separators 72 are designed so that any two are all that are required to process the total amount of fluid passing through the satellite station 10. With the same rate of flow of gas through the orifice meter 172, and liquid through the flowmeter 166, a signal warning of an increase in pressure will be transmitted to the control portion 66 of the satellite station from the sensor 160 in the manifold 158, indicating that there is a problem. Furthermore, the closing ofa valve 168 can be made to actuate an electric switch, which in turn will provide a signal indicating which separator is malfunctioning. The production stream through the plugged separator 72 would then be cut off by closing the respective shutoff valve 163 so that the respective separator 72 can be serviced by personnel within the satellite station 10.

The portion of the schematic diagram designated as the TFL Fluid Supply System contains a fluid storage means 178, which corresponds to the open-bottomed fluid storage section 70 of the satellite station 10 as shown in FIG. 2. The storage means 178 is connected to a first inlet port of the three-way two-position valve 180 through a line 190 having a salt water sensor 188 therein to provide a signal in the control section of the satellite station 10 indicating that the storage means 178 is empty of treating fluid and now contains only salt water. The other inlet port of the three-way two-position valve 180, as previously discussed, is connected to a source of clean oil through the line 174 extending from the manifold 175 in the PRODUCTION SYSTEM portion of the schematic diagram. The outlet of the three-way two-position valve 180 is operatively connected to the inlet of the pump portion of the turbine-pump 112, the outlet of the pump portion of the turbinepump '112 being connected to an inlet of a manifold 182 through a conduit 184. The power for driving the pump portion of the turbine-pump 112 is provided by gas under pressure obtained through the line 118 from the auxiliary separator 161, which is fed with produced fluid at wellhead pressure from the Well and Wellhead Equipment portion of the system as previously outlined. By opening and closing a valve 176 in the line 118, the operation of the turbine-pump 112 may be controlled. From the manifold 182 the clean oil and/or the treating fluid, under pressure, is pumped through one or more of the outlet lines 192 at a time, each of the outlet lines 192 having a check valve 194 and a selectively actuated cutoff valve 196 therein from which the fluid is directed through the respective line 122 into the Well and Wellhead Equipment portion of the schematic diagram where it is directed into the bypass conduit 124 between the TFL tool storage chamber 146 and the shutoff valve 148. Outlet lines 192, each having a one-way check valve 194 and a shutoff valve 196' therein, are connected to the bypass conduits of the Well and Wellhead Equipment portions of the other wells (not shown) producing through the respective satellite station 10.

To commence a TFL maintenance and/or testing procedure, valves 148 and 154 in the Well and Wellhead Equipment portion would both be closed. The shutoff valve 176, in the TFL Fluid Supply System, connected to the input of the turbine-pump 112 would be open to activate the turbine portion. For paraffin removal, for instance, a paraffin solvent and corrosion inhibitor stored in the storage means 178 would first be drawn into the input of the pump section of the turbine-pump 112 by the proper positioning of the valve 180. After pumping approximately one barrel of treating fluid through the valve 180, the position of the valve would be changed so that the oil from line 174 would then be supplied to the pump portion of the turbine-pump 112. One or more of the valves 196, 196' would be open to permit the fluid driven by the turbine-pump 112 to exit from the header 182 through a line 122 to apply fluid pressure in the section of the bypass conduit 124, of the Well and Wellhead Equipment portion, between the valve 148 and the storage means 146. With the valve 148 closed, the fluid driven through line 122 into the bypass conduit 124, behind the storage means 146, will cause a paraffin cutting tool 126 positioned within the storage means 146 to be propelled down through the curved tubing section 56 of the connector unit 54 and down through the wellhead 14 of the respective well 138. The piston section of the tool 126 is not completely sealed within the tubing of the well 138 in which it moves so that by the time the tool is down in the well, at the lower end of the paraffin deposition zone,-all of the treating fluid is in the well ahead of the tool. When the tool 126 reaches the end of its travel, above the storm choke 140, the valve 176, in the TFL Fluid Supply System portion, controlling the turbine-pump 112, would be shut causing the turbine-pump 112 to cease operation. The shutoff valve 148 in the bypass conduit 124 is then opened causing the TFL tool 126 to be returned up the well 138 by the fluid being produced, which now is directed into the downstream portion of the branch conduit 76 through the bypass conduit 124. When the TFL tool 126 has reentered the storage chamber 146, an indication of this condition will be given in the control section 66. A switching means providing this function is shown in the Dean U.S. Pat. No. 3,396,789, discussed above. At this time, the valve 148, in the bypass conduit 124, will be shut and the valve 154, in the branch conduit 76, will be reopened, returning the well to production through the branch conduit 76. All of the previously described steps can be sequentially performed by an operator in the control section 66 of the satellite station 10, by remote control from the floating master station 20, or by a programmed computer, or by a combination of the aforementioned methods.

FIG. 5 illustrates a modification in which an electric motor 198 is utilized for driving a pump 200. With the substitution of the electric motor 198 and the pump 200 for the turbinepump 112 (shown in FIG. 4), the gas line 118 is eliminated and the only exit line from the manifold is the line 130. The remainder of the TFL Fluid Supply System (shown in FIG. 5) is identical to that shown in FIG. 4, therefore being a storage means 178 connected to one inlet of a three-way twoposition valve 180 through a line having a salt water sensor 188 therein. The other inlet of the three-way two-position valve 180 is connected to the line 174 as shown in FIG. 4

which is connected at the other end thereof to a clean oil source in the separators 72. The outlet of the three-way twoposition valve 180 is operatively connected to the inlet of the pump 200. The outlet of the pump 200 is in turn connected, through the line 184, to the header 182, as shown in FIG. 4. The identical procedure would be followed with the exception that electrical power would be used to operate the electric motor 198 to drive the pump 200.

FIG. 6 shows the modified Production System to be used with the typical high gas-oil ratio high pressure well. This modified Production System is utilized with the Well and Wellhead Equipment portion and TFL FLUID SUPPLY SYSTEM portion of the schematic diagram of FIG. 4. As the produced fluid is directed from the branch conduit 76 through a variable choke 156' and a check valve 157, it is collected in a primary manifold 202 (generally similar to the manifold 78 shown in FIG. 2). The produced fluid in the manifold 202, having a high gas content, is now quite cold due to expansion in the choke 156'. This cold fluid passes out of the manifold 202 through a line 204 extending through a heat exchanger unit 206 (corresponding to the heat exchanger unit 74 of FIG. 2). The fluid, warmed up in the heat exchanger unit 206, enters a secondary manifold 208 from which it is directed into three separators 72. A pressure sensor 209 and a temperature probe 238 are located in the secondary manifold 208. From the separators 72 the major part of the produced liquid is collected in the manifold 164' after which it is removed through a line 102' having a flowmeter 166 therein, the outlet of the flow meter 166 being connected to the inlet ofa shipping line 18 connecting the satellite station with a distant storage facility. Again, clean oil is picked up by lines 108' and is directed through line 174' to the clean oil supply inlet of the three-way two-position valve, as shown in FIG. 4. The gas exiting from the separators 72, through lines 120' is collected in the manifold 170' from which it is, in the main, transmitted through a line 210 from the orifice meter 172, through a safety pop-off valve 214, to a gas injection well 212, for disposal in shallow sand formations. The gas enters the injection well 212 through the wellhead 216 thereof having a high-low fail-safe valve 218 and a manually operated valve 220. There is also a storm choke 222 beneath the marine bottom in the injection well 212. If the back pressure in the shallow sand formations being used for disposal should rise above a preset limit of the pop-off safety valve 214, the gas will be directed instead through a line 134' to the surface where it will be flared. To heat the cold fluids within the heat exchanger unit 206, warm water, at 150 to 170 F., is obtained from the TD 228 of a water injection well 226 producing through a wellhead 227 comprising a manual valve 230 and an automatic setting valve 232, and a rotary choke 234 having a pressure differential indicating device 236 located thereacross. The warm water flows through the heat exchanger unit 206, past a series of coils 205, in the line 104. From the heat exchanger unit 206, the then cooled water is directed out through line 240 into the surrounding water near the marine bottom. The rotary choke 234 is operated automatically in response to a temperature signal obtained from the temperature probe 238 previously described as located in the primary manifold 208 downstream of the heat exchanger unit 206. As the temperature sensed by the temperature probe 238 decreases, the choke 234 is opened further. If the temperature indicated reaches a specified low level, the satellite station 10 is completely shut in.

FIG. 7 is a schematic diagram of another modification of the Production System of FIG. 4, for a typical medium gas-oil ratio, medium pressure well. A well is produced in the same manner as in the previous two examples utilizing the same type of well and wellhead equipment. In this modification the fluid, entering the Production System portion through a branch conduit 76, is directed through a one-way valve 241 into a heat exchanger conduit 242 which traverses a heat exchanger unit 244. The produced fluid having been produced from a TD of l0,000 feet makes its first pass through the heat exchanger unit 244 at a temperature of to F. Upon exiting from the heat exchanger unit 244, a pressure cut is taken through a variable choke 245. The now cold fluids are passed back through the heat exchanger unit 244 by the traversing heat exchanger conduit 245 to raise the temperature in the expanded fluid to a prescribed minimum to prevent hydrate formation and wax deposition. From the conduit 245 the fluid passes into a collector manifold 246 containing a pressure sensor 238 and temperature probe 209. In collector manifold 246, the fluid from the heat exchanger conduit is combined with the pressure cut fluid from the other wells of the satellite stations through heat exchanger lines 245. The fluid from each well has previously been directed through the heat exchanger unit 244, had a pressure cut taken and then been passed back through the heat exchanger unit 244 through separate conduits. The combined fluid in the collector manifold 246 is directed out through a conduit 247, making a final pass across the heat exchanger unit 244 into another collector manifold 248. From the manifold 248, the fluid is divided into separate streams and directed into separators 72' through lines 249. The remainder of the fluid system is identical to that already discussed with respect to FIG. 4. If the temperature indicated by the temperature probe 209' decreases below a specified value, all the wells of the satellite station 10 are shut in.

The schematic diagrams of FIGS. 4-7 illustrate examples of systems to be used in specific cases. However, the features of the various Figures can be combined in different arrangements to suit various conditions. For instance, the electricmotor-drive-pump 200 of FIG. 5 could be used with the modifications of FIGS. 6 and 7.

FIG. 8 illustrates a modified satellite station 10, similar to the satellite station 10 of FIGS. 1 and 2, having the added advantage of being able to be installed prior to completing any of the production wells through the ring 51' of the base template 28. In this embodiment, instead of using cradling arms as illustrated in FIG. 2, the satellite body is held in the satellite base 28 by a central sleeve 250 depending from the lower end of the satellite body 15' and automatic spring-loaded latches (not shown) over the upper end of the well conductor pipe of the water well 52. The latches can be disabled by a hydraulic pressure applied through the conduit 252 extending between a manifold 254, forming a portion of the framing of the base template 28', at the inner end, and a quick-disconnect coupling section 256, at the outer end. The outer end of the conduit is supported by a skeletal frame 258 to displace the coupling section 256 outward of the well conductor pipes 34'. The arrangement of the equipment within the satellite body 15' is substantially the same as the arrangement within the satellite body 15 of the earlier discussed embodiment with the exception of the orientation of the TFL tool 126 and the associated hydraulic circuitry. In this instance, the connector units 54 are not permanently attached to the satellite body 15' but instead are stabbed-over tubing nipples 260 extending vertically out of the upper end of the satellite body 15'. When a well is to be completed through one of the upstanding well conductor pipes 34', a wellhead 14 is first mounted on the respective well conductor pipe 34. A connector unit 54 is later lowered from the surface to make the connection between the wellhead 14 and the satellite body 15'. The connector unit 54' consists of a curved tubing section 56' and a vertical lubricator section 58'. The lower end of the lubricator section 58' is stabbed over the tubing (not shown) extending vertically out of the upper end of the wellhead 14, while the outer vertical free ends of the curved tubing section 54 stabs over the respective ones of the upstanding tubing nipples 260 extending out of the upper end of the satellite body 15'. In this manner, with each connector section 54' being individually engaged between the wellhead 14' and the respective upstanding tubing nipples 260, greater tolerances can be allowed in installing the satellite body 15'. Furthermore, an individual well can be produced through the satellite station 10' while the remaining wells are still being drilled and completed. The verlOl024 (HA1 tical orientation of the tubing nipples 260 extending vertically into the satellite body 15 presents no problem, each of the TFL storage chambers 146' is reoriented into a vertical position so as to be coaxial with the respective tubing nipples 260. The vertical position of the storage chamber 146' permits the TFL tool 126' stored therewithin to move easily into respective tubing nipples 260 so that it can be pumped, under fluid pressure, through a full 180 bend in the tubing sections 56 of the connector unit 54 Such a bend, of 180, will not present any insurmountable problems requiring only that the wells be spaced out far enough from the satellite body 15' to obtain a -foot radius bend in the conduit. Stab-over connections, as discussed in this application, are more fully described in the Manning application Ser. No. 663,799 now U.S. Pat. No. 3,504,740.

Although the present invention has been described in connection with details of the specific embodiments thereof, it is to be understood that such details are not intended to limit the scope of the invention. The terms and expressions employed are used in a descriptive and not a limiting sense and there is no intention of excluding such equivalents in the invention described as fall within the scope of the claims. Now having described the apparatus and methods herein disclosed, reference should be had to the claims which follow.

What is claimed is:

l. A subsea production satellite system comprising: a base template supported-beneath the surface of a body of water; a plurality of wells completed through said base template, beneath the surface of said body of water; a fully submerigible production satellite body releasably mounted on said base template; and means for releasably fluidly connecting each of said plurality of wells with the interior ofsaid production satellite body whereby fluids produced through said plurality of wells are gathered within said production satellite body.

2. A subsea production satellite system, as recited in claim 9, wherein said base template has an annular portion extending out beyond said satellite body installed thereon, said plurality of wells being completed through said annular portion just outward ofsaid satellite body.

3. A subsea production satellite system, as recited in claim 1, wherein said base template extends out beyond said satellite body installed thereon, each of said plurality of wells being completed through a vertical well conductor pipe forming a portion of said base template.

4. A subsea production satellite system, as recited in claim 9, wherein said production satellite body comprises a watertight shell enclosing production equipment; means for transferring personnel into said satellite body through the submerged upper end thereof.

5. A subsea production satellite system, as recited in claim I, wherein said plurality of wells are completed through said base template in an enclosed pattern.

6. A subsea production satellite system, as recited in claim 5, wherein said enclosed pattern is a circle.

7. A subsea production satellite system, as recited in claim 9, wherein said base template has an annular portion through which said plurality of wells are completed in a circular pattern; means for releasably mounting said satellite body on said base template, said mounting means comprising a portion fixed to said base template and coaxially located with respect to said annular portion.

8. A subsea production satellite system, as recited in claim 14, wherein said portion of said mounting means fixed to said base template comprises a vertical pipe.

9. A subsea production satellite system, as recited in claim 1, wherein said production satellite body is divided into verti' cally separated compartments.

10. A subsea production satellite system, as recited in claim 1, wherein the lowest of said vertical compartments is a storage area for well treating fluids and is open to said body of water at the lower end thereof.

11. A subsea production satellite system, as recited in claim 1, wherein said production satellite body is a vertically oriented cylinder having rounded ends; means for releasably mounting said satellite body on said base template, said releasable mounting means comprising portions fixed to said base template and to the lower rounded end of said satellite body.

12. A subsea production satellite system, as recited in claim 11, wherein said means for releasably fluidly connecting each of said plurality of wells with the interior of said production satellite body are connector units angularly spaced around the shell of said satellite body, each of said connector units comprising at least one vertical tubing section; means at the lower end of said at least one vertical tubing section for releasably connecting said connector unit to at least one tubing nipple extending upwardly from a subsea wellhead through which one of said plurality of wells is completed.

13. A subsea production satellite system, as recited in claim 20, wherein each of said connector units further comprises a curved tubing section extending between each of said at least one vertical sections and the vertically oriented cylindrical shell of said production satellite body,'said curved tubing section intersecting said shell perpendicularly and extending into said production satellite body to connect a production passage of a subsea wellhead with production equipment within said production satellite body.

14. A subsea production satellite system, as recited in claim 13, wherein said curved tubing section of said connector units is permanently fixed and extends integrally through said shell of said production satellite body.

15. A subsea production satellite system, as recited in claim 13, wherein said at least one vertical section extends above a point at which said curved tubing section of said respective connector unit joins said at least one vertical section whereby workover operations may be performed through the respective subsea wellhead from above without removing said connector unit or the entire production satellite body.

16. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, including the following steps:

a. setting a base template, through which a plurality of wells are to be drilled, on a marine bottom beneath the surface of a body of water;

b. drilling said plurality of wells through said base template set on said marine bottom, at least some of said plurality of wells being directionally drilled;

c. completing said plurality of wells, drilled through said base template, with subsea wellheads on said base template; and

d. releasably installing a production satellite body beneath the surface of said body of water on said base template and releasably connecting said production satellite body with said plurality of completed wells through subsea wellheads thereof.

17. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein subsea wellheads, completing said plurality of subsea wells, are arranged in a circular pattern on said base template.

18. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein said production satellite body is substantially simultaneously brought into connection with all of the subsea wellheads of said plurality of completed wells as said production satellite body is releasably installed on said base template.

19. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein said plurality of wells are drilled and completed, and said production satellite body is installed substantially from a floating station.

20. A subsea system comprising in combination:

a. an underwater satellite body positioned at a relative central position, said satellite body having a compartment capable of sustaining human life;

b. a plurality of underwater wells surrounding said satellite and spaced therefrom;

c. coupling means for connecting at least one ofsaid wells to said satellite body, said coupling means being adaptable for the passage of materials and through-flowline-tools between said satellite body, and said at least one well; and

d. means in said satellite body cooperable with said coupling means for supplying a well servicing tool to said coupling means whereby said well servicing tool may pass from said satellite body, through said coupling means, and into said well.

21. A base template for releasably supporting a subsea production satellite on a marine bottom comprising:

a support means comprising a generally flat annular member;

a plurality of guide means through said annular member,

each of said guide means comprising a vertical well conductor pipe and each being spaced on said annular member from others of said guide means, each of said guide means extending at least partially through said annular member and each being adapted to have a well drilled and completed therethrough; and

means on said support means for supporting and releasably fixing a fully submerged, production satellite body on said base template so that said satellite is in a fixed relationship to wells drilled and completed through said guide means when said satellite is in position on said base template, said fixing means'comprising a central vertical pipe within said annular member fixed thereto by an open framework.

22. A base template, as recited in claim 21, wherein said central vertical pipe is a well conductor pipe whereby a water well is drilled in a location which will be directly beneath a satellite body to be installed thereover.

7005 UNITED STATES PATENT OFFICE CERTIFICATE 0F CGRREQTTQN Patent No. 3 ,643 ,736 Dated February 22, 1972 Inventor() William .Tallev. Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

First page, References Cited, last line, "Towsend" should be 7 "Townsend- Attorney, --Drude Faulconer-- should be inserted. Column 4, line 18, 'Ser. No. 649,959" not identified with U.S.

' Patent No. 3,520,358; 7 line 58, "663 ,798" not identified with U.S. Patent No. 3,545,539, Column 6, line 73, a -period,(.) should be inserted after "oil". Column 10, line 54, --for-- should be inserted before 7 I "providing". I Column 11, line 55, "104" should be --204-- Column 13, line 37, "9" should. be --l--;

line 47, "9" should be --l--; line 57 "9" should be --l--' line 65 "14" should be -1 line 7 l: '-'l"-should be --9-'-." Column 14, line 18, "20" should be --'-l2-.

Signed and sealed this 22nd dayxof August 1972.

(SEAL) Attic) S t2 EDWARD M..l""LET JHER,JR. ROBERT GOITSGHALK Attesting, Officer Commissionerof Patents FORM 301050 HO'GQ) I uscoMM-Dc 60376 P69 U,5, GOVERNMENT PRINTING OFFICE! I559 0366-33 

1. A subsea production satellite system comprising: a base template supported beneath the surface of a body of water; a plurality of wells completed through said base template, beneath the surface of said body of water; a fully submerigible production satellite body releasably mounted on said base template; and means for releasably fluidly connecting each of said plurality of wells with the interior of said production satellite body whereby fluids produced through said plurality of wells are gathered within said production satellite body.
 2. A subsea production satellite system, as recited in claim 9, wherein said base template has an annular portion extending out beyond said satellite body installed thereon, said plurality of wells being completed through said annular portion just outward of said satellite body.
 3. A subsea production satellite system, as recited in claim 1, wherein said base template extends out beyond said satellite body installed thereon, each of said plurality of wells being completed through a vertical well conductor pipe forming a portion of said base template.
 4. A subsea production satellite system, as recited in claim 9, wherein said production satellite body comprises a watertight shell enclosing production equipment; means for transferring personnel into said satellite body through the submerged upper end thereof.
 5. A subsea production satellite system, as recited in claim 1, wherein said plurality of wells are completed through said base template in an enclosed pattern.
 6. A subsea production satellite system, as recited in claim 5, wherein said enclosed pattern is a circle.
 7. A subsea production satellite system, as recited in claim 9, wherein said base template has an annular portion through which said plurality of wells are completed in a circular pattern; means for releasably mounting said satellite body on said base template, said mounting means comprising a portion fixed to said base template and coaxially located with respect to said annular portion.
 8. A subsea production satellite system, as recited in claim 14, wherein said portion of said mounting means fixed to said base template comprises a vertical pipe.
 9. A subsea production satellite system, as recited in claim 1, wherein said production satellite body is divided into vertically separated compartments.
 10. A subsea production satellite system, as recited in claim 1, wherein the lowest of said vertical compartments is a storage area for well treating fluids and is open to said body of water at the lower end thereof.
 11. A subsea production satellite system, as recited in claim 1, wherein said production satellite body is a vertically oriented cylinder having rounded ends; means for releasably mounting said satellite body on said base template, said releasable mounting means comprising portions fixed to said base template and to the lower rounded end of said satellite body.
 12. A subsea production satellite system, as recited in claim 11, wherein said means for releasably fluidly connecting each of said plurality of wells with the interior of said production satellite body are connector units angularly spaced around the shell of said satellite body, each of said connector units comprising at least one vertical tubing section; means at the lower end of said at least one vertical tubing sEction for releasably connecting said connector unit to at least one tubing nipple extending upwardly from a subsea wellhead through which one of said plurality of wells is completed.
 13. A subsea production satellite system, as recited in claim 20, wherein each of said connector units further comprises a curved tubing section extending between each of said at least one vertical sections and the vertically oriented cylindrical shell of said production satellite body, said curved tubing section intersecting said shell perpendicularly and extending into said production satellite body to connect a production passage of a subsea wellhead with production equipment within said production satellite body.
 14. A subsea production satellite system, as recited in claim 13, wherein said curved tubing section of said connector units is permanently fixed and extends integrally through said shell of said production satellite body.
 15. A subsea production satellite system, as recited in claim 13, wherein said at least one vertical section extends above a point at which said curved tubing section of said respective connector unit joins said at least one vertical section whereby workover operations may be performed through the respective subsea wellhead from above without removing said connector unit or the entire production satellite body.
 16. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, including the following steps: a. setting a base template, through which a plurality of wells are to be drilled, on a marine bottom beneath the surface of a body of water; b. drilling said plurality of wells through said base template set on said marine bottom, at least some of said plurality of wells being directionally drilled; c. completing said plurality of wells, drilled through said base template, with subsea wellheads on said base template; and d. releasably installing a production satellite body beneath the surface of said body of water on said base template and releasably connecting said production satellite body with said plurality of completed wells through subsea wellheads thereof.
 17. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein subsea wellheads, completing said plurality of subsea wells, are arranged in a circular pattern on said base template.
 18. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein said production satellite body is substantially simultaneously brought into connection with all of the subsea wellheads of said plurality of completed wells as said production satellite body is releasably installed on said base template.
 19. A method for exploiting subaqueous deposits of fluid minerals through a subsea production satellite station, as recited in claim 16, wherein said plurality of wells are drilled and completed, and said production satellite body is installed substantially from a floating station.
 20. A subsea system comprising in combination: a. an underwater satellite body positioned at a relative central position, said satellite body having a compartment capable of sustaining human life; b. a plurality of underwater wells surrounding said satellite and spaced therefrom; c. coupling means for connecting at least one of said wells to said satellite body, said coupling means being adaptable for the passage of materials and through-flowline-tools between said satellite body and said at least one well; and d. means in said satellite body cooperable with said coupling means for supplying a well servicing tool to said coupling means whereby said well servicing tool may pass from said satellite body, through said coupling means, and into said well.
 21. A base template for releasably supporting a subsea production satellite on a marine bottom comprising: a support mEans comprising a generally flat annular member; a plurality of guide means through said annular member, each of said guide means comprising a vertical well conductor pipe and each being spaced on said annular member from others of said guide means, each of said guide means extending at least partially through said annular member and each being adapted to have a well drilled and completed therethrough; and means on said support means for supporting and releasably fixing a fully submerged, production satellite body on said base template so that said satellite is in a fixed relationship to wells drilled and completed through said guide means when said satellite is in position on said base template, said fixing means comprising a central vertical pipe within said annular member fixed thereto by an open framework.
 22. A base template, as recited in claim 21, wherein said central vertical pipe is a well conductor pipe whereby a water well is drilled in a location which will be directly beneath a satellite body to be installed thereover. 